I recently came across this article by Michael Drake, the founder of Drakes of London, where he details his sartorial philosophy. The whole thing is worth reading, but here are some highlights:
Start with the shirt. Keep it simple; blue is always a good colour, as is white, in solids, small stripes or checks. Avoid extremes; theatrical collar shapes are really dumb, as is edge stitching or fancy-coloured buttonholes. Go for softness and simplicity; allow the make to show through.
Avoid jacquard weaves, anything that looks shiny, and select twill weaves only if it’s a cotton flannel. Opt for two-ply, crisp cottons. If the fabric is too fine chest hair will show through and this is, let’s be delicate, not a good look. Best stick to 2x100s or 2x120s cotton broadcloth. Good buttons are mother-of-pearl, of course.
Next the tie. The tie is important not only because it’s so much the focus of attention, but because it’s more symbolic than utilitarian. The best ties are hand made, never stitched by machine. You have a suit made in the round, and so the tie should be three-dimensional as well.
Avoid extremes: no wider than nine centimetres and no narrower than seven. Eight will look right on any occasion.
The pattern should not be overly designed, with too many colours, or too shiny; although solid satin in navy, grey or purple is fine for the evening, for a more formal look. The time-honoured tradition of lighter coloured ties in the morning, a little darker in the afternoon and darker still in the evening is hard to beat.
Socks are another give away. Never wear short socks with a suit. Navy socks always work with brown shoes but black socks do not with brown. Personally I am inclined to wear purple socks with almost anything, and like to think of it merely as a signature eccentricity.
Avoid extremes in shoes: those that are too flamboyant, too pointy (or too square for that matter) or over designed. It’s too easy for shoes to call attention to themselves and spoil the overall effect.
The idea is to not look as if you have just arrived on the boat from Naples. The best-dressed Neapolitans aim for an understated English style.
There are a small number of things to quibble with in the article. For example, where Drake recommends the Half-Windsor, I would recommend the Pratt, as it’s less ostentatious. However, the whole of the article is excellent. Drake’s philosophy, combined with Luciano Barbera’s, will teach you the general practices of conservative European style, at least in the tailored menswear tradition. This isn’t to say that this is the only way to dress, but it’s an excellent and elegant ideal to shoot for if you’re just starting out.